From 8ff5c19ebdfebdcafc0b2e777d8b805ea89b8d86 Mon Sep 17 00:00:00 2001 From: Reid Kleckner Date: Wed, 30 Sep 2009 20:15:38 +0000 Subject: Fix integer overflow in instruction scheduling. This can happen if we have basic blocks that are so long that their size overflows a short. Also assert that overflow does not happen in the future, as requested by Evan. This fixes PR4401. llvm-svn: 83159 --- llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp') diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp index a9d18784608..bd6e04805f1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp @@ -278,6 +278,7 @@ void ScheduleDAGRRList::CapturePred(SDep *PredEdge) { AvailableQueue->remove(PredSU); } + assert(PredSU->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!"); ++PredSU->NumSuccsLeft; } @@ -824,17 +825,17 @@ void ScheduleDAGRRList::ListScheduleBottomUp() { /// the AvailableQueue if the count reaches zero. Also update its cycle bound. void ScheduleDAGRRList::ReleaseSucc(SUnit *SU, const SDep *SuccEdge) { SUnit *SuccSU = SuccEdge->getSUnit(); - --SuccSU->NumPredsLeft; - + #ifndef NDEBUG - if (SuccSU->NumPredsLeft < 0) { + if (SuccSU->NumPredsLeft == 0) { errs() << "*** Scheduling failed! ***\n"; SuccSU->dump(this); errs() << " has been released too many times!\n"; llvm_unreachable(0); } #endif - + --SuccSU->NumPredsLeft; + // If all the node's predecessors are scheduled, this node is ready // to be scheduled. Ignore the special ExitSU node. if (SuccSU->NumPredsLeft == 0 && SuccSU != &ExitSU) { -- cgit v1.2.3